Area Forecast Discussion
Issued by NWS Los Angeles, CA

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154
FXUS66 KLOX 121303
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
503 AM PST FRI FEB 12 2016

.SYNOPSIS...
AN UPPER LEVEL TROUGH PASSING TO THE NORTH WILL PROVIDE BRIEF
COOLING TO THE REGION BY SATURDAY. HIGH PRESSURE ALOFT BUILDING
IN FROM THE WEST AND A RETURN OF OFFSHORE WINDS WILL ALLOW
TEMPERATURES TO REBOUND TO NEAR RECORD TERRITORY BY MONDAY. A
SECOND MORE SIGNIFICANT AREA OF LOW PRESSURE SHOULD BRING A CHANCE
OF PRECIPITATION TO THE FORECAST AREA LATER THIS WEEK.

&&

.SHORT TERM...(TDY-SUN)

A WEAK UPPER TROUGH WAS BRINGING SOME MID-HIGH LEVEL CLOUDS ACROSS
MUCH OF SLO/SBA COUNTY THIS MORNING. THIS UPPER TROUGH WILL BRING
SOME RAIN TO THE NORTHERN PART OF THE STATE TODAY...BUT JUST KEEP
HIGH CLOUDS MOVING OVER THE REGION TODAY. WITH THE OFFSHORE
GRADIENT WEAKENING...SOME DENSE FOG HAS DEVELOPED ACROSS THE
CENTRAL COAST AND THE ADJACENT COASTAL WATERS THIS MORNING. THERE
IS A SLIGHT CHANCE THAT SOME PATCHY DENSE FOG COULD DEVELOP ACROSS
PORTIONS OF THE SANTA BARBARA SOUTH COAST. NOT EXPECTING ANY
STRATUS TO FORM OVER L.A AND VENTURA COUNTY THIS MORNING DUE TO
THE WEAK OFFSHORE FLOW. THE FOG THAT IS ACROSS PORTIONS OF THE
CENTRAL COAST SHOULD SCOUR OUT EARLY AS SOME EASTERLY FLOW FROM
THE SAN LUCIA MTNS WILL PICK UP LATER THIS MORNING. HIGH TEMPS
WILL CONTINUE TO TREND A FEW DEGREES COOLER ACROSS COAST AND
VALLEYS AS THE OFFSHORE FLOW CONTINUES TO WEAKEN AND THE UPPER
RIDGE SHIFTS OVER TO A WEAK TROUGH OVER THE AREA LATE TODAY. THE
SEABREEZE WILL PICK UP THIS AFTERNOON GIVING COASTAL AREAS THE
BEST COOLING. HIGH TEMPS WILL REMAIN WELL ABOVE NORMAL FOR AREAS
AWAY FROM THE IMMEDIATE COAST. EXPECT HIGHS TO REACH THE UPPER 70S
TO A FEW 80S ALONG THE LA/VTU COASTAL ZONES...WHILE THE VALLEYS
WARM INTO THE MID 80S WITH A FEW SITES REACHING THE UPPER 80S.
HIGH TEMPS WILL BE A BIT COOLER FOR AREAS N OF VENTURA COUNTY.

THE FORECAST FOR TONIGHT WILL BE A BIT TRICKIER IN RESPECT TO LOW
CLOUDS AND STRATUS. THE SURFACE OFFSHORE/ONSHORE GRADIENT WILL BE
NEAR NEUTRAL TONIGHT INTO SATURDAY MORNING. SO STRATUS WILL BE
ABLE TO CREEP A BIT CLOSER TO THE LA/VTU COAST. HAVE PUT A RETURN
OF LOW CLOUDS AND FOG TO THE CENTRAL COAST AND A CHANCE FOR SOME
PATCHY DENSE STRATUS ACROSS PORTIONS OF THE L.A /VTU AND POSSIBLY
THE SBA SOUTH COAST LATE TONIGHT INTO SATURDAY MORNING. MORE
MARGINAL WIDESPREAD COOLING WILL CONTINUE AS A WEAK UPPER LVL
DISTURBANCE MOVES OVER THE REGION SATURDAY. THE ONLY VISIBLE
AFFECTS WILL BE SOME HIGH CLOUDS MOVING OVER THE REGION WITH THE
COOLER TEMPS. BY SATURDAY EVENING...NORTHERLY WINDS WILL INCREASE
BEHIND THE EXITING UPPER DISTURBANCE. EXPECT GUSTY NW-N WINDS TO
INCREASE ACROSS THE SBA COUNTY MTNS AND WIND PRONE PASSES AND
CANYONS OF THE SBA SOUTH COAST SATURDAY EVE THROUGH THE OVERNIGHT
HOURS. ALSO...ACROSS THE I-5 CORRIDOR INTO THE SANTA CLARITA AND
SAN FERNANDO VALLEYS. WINDS WILL REMAIN BELOW WIND ADVISORY
THRESHOLDS.

FOR SUNDAY...SKIES WILL BE MOSTLY SUNNY WITH WINDS CONTINUING IN
THE SAME AREAS...BUT WIND DOWN OVER SBA COUNTY. THERE COULD BE
SOME LOCAL GUSTY WINDS BELOW THE HOLLYWOOD HILLS AND SANTA MONICA
MOUNTAINS WHERE THE MARATHON RUNNERS WILL BE SUNDAY MORNING. NOT
EXPECTING ANY STRATUS SUNDAY MORNING DUE TO THE OFFSHORE WINDS.
HIGH TEMPS WILL REBOUND AS WELL 4 TO 8 DEGREES FOR COAST AND
COASTAL VALLEYS AS OFFSHORE FLOW KICKS IN.

.LONG TERM...(MON-THU)

BY MONDAY...A RATHER STRONG 589DM HIGH SETS UP JUST OFF THE
SOUTHERN AND CENTRAL COAST WITH A WEAK CUTOFF LOW JUST TO THE SW
OF THE HIGH. AT THE SURFACE...A RELATIVELY STRONG OFFSHORE
SURFACE GRADIENT SETS UP AS A 1030MB HIGH BUILDS IN OVER NRN
NEVADA. THIS WILL TRANSLATE TO WARMER TEMPS AND A MODERATE SANTA
ANA WIND EVENT. LAX-DAG SFC GRAD WAS -6.8MB. SOME UPPER SUPPORT
OVER THE MOUNTAINS...BUT NOT MUCH OVER COAST AND VALLEYS. BY
TUESDAY THE UPPER RIDGE AXIS WILL WEAKEN BUT PERSIST OVERHEAD
WHILE ANOTHER UPPER TROUGH STARTS TO DIG SOUTH TOWARDS NRN CAL.
HIGH TEMPS WILL REMAIN CLOSE TO MONDAY`S FOR AREAS S OF POINT
CONCEPTION...BUT SHOULD SEE SOME MINOR COOLING FOR AREAS TO THE
NORTH. EXPECT HIGHS FOR LA/VTU COAST AND COASTAL VALLEYS TO BE IN
THE MID TO UPPER 80S...WITH COOLER CONDS FOR AREAS TO THE NORTH
AND INTERIOR LOCATIONS.

BY WEDNESDAY...A BROAD TROUGH WITH A MORE SIGNIFICANT COLD FRONT
WILL MOVE INTO NORTHERN CALIFORNIA...THEN SLIDE SOUTH TO BRING
RAIN INTO THE FORECAST AREA BY WEDNESDAY NIGHT OR THURSDAY. WITH
THE MODELS CONSISTENT IN THE SLOW DOWN OF THE APPROACHING STORM
HAVE BACKED OFF POPS 6-12 HOURS. LOOKS LIKE THE BRUNT OF THE STORM
WILL BE THURSDAY INTO THURSDAY NIGHT...WITH POSSIBLE RESIDUAL
SHOWERS INTO FRIDAY. TOO EARLY TO GET A HANDLE OF RAINFALL
AMOUNTS...BUT LOOKS LIKE THE SNOW LEVEL WILL BEGIN ABOVE 6500
FT...THEN LOWER TO BETWEEN 5500 AND 6000 FT THURSDAY-THURSDAY
NIGHT. HIGH TEMPS WILL ONLY REACH THE MID 70S WEDNESDAY...WITH
EVEN COOLER CONDS ON THURSDAY WITH THE RAIN.

&&

.AVIATION...12/1230Z.

AT 12Z...THE MARINE LAYER DEPTH AT KLAX WAS AROUND 300 FEET DEEP.
THE TOP OF THE INVERSION WAS AT 1200 FEET WITH A TEMPERATURE OF
24 DEGREES CELSIUS.

PATCHY LOW CLOUDS AND DENSE FOG WILL AFFECT THE CENTRAL COAST
THROUGH MID MORNING...WITH MOSTLY LIFR TO VLIFR CONDS.
ELSEWHERE...SOME LOW CLOUDS WITH IFR CONDS ARE POSSIBLE ACROSS
COASTAL SECTIONS OF SRN SBA AND VTU COUNTIES...MAINLY NEAR THE
BEACHES...BUT CONFIDENCE IN THIS IS LOW. EXPECT LOW CLOUDS WITH
IFR TO LIFR CONDS TO SPREAD INTO THE CENTRAL COAST AFTER 00Z...
AND COASTAL SECTIONS OF L.A...VTU AND SRN SBA COUNTIES AFTER 05Z.

KLAX...MODERATE TO HIGH CONFIDENCE IN THE 12Z TAF. THERE IS A 20
PERCENT CHANCE OF MVFR VSBYS BETWEEN 12Z AND 16Z...AND A 10 PERCENT
CHANCE OF LIFR CONDITIONS DURING THAT TIME. THERE IS A 20 PERCENT
CHANCE THAT IFR CONDS THIS EVENING WILL ARRIVE AS EARLY AS 03Z.

KBUR...HIGH CONFIDENCE IN THE 12Z TAF WITH VFR CONDITIONS
EXPECTED THRU THE PERIOD.

&&

.MARINE...12/330 AM...

SEAS WILL RISE ABOVE SCA THRESHOLDS OF 10 FT IN ALL OUTER WATERS
AND ACROSS THE INNER WATERS N OF PT CONCEPTION THIS MORNING...AND
REMAIN AT OR ABOVE 10 FT THRU SUNDAY EVENING. WINDS SHOULD REACH
SCA LEVELS AT TIMES THRU SUN EVENING ACROSS THE OUTER WATERS...
BUT PROBABLY STAY JUST BELOW SCA LEVELS (FOR WINDS) ACROSS THE NRN
INNER WATERS. AS A RESULT...A SCA FOR SEAS IS IN EFFECT THERE.

THERE IS A 30 PERCENT CHANCE THAT A SCA FOR HAZARDOUS SEAS WILL BE
NEEDED ACROSS THE SBA CHANNEL TONIGHT THRU SAT NIGHT...AND A 20
PERCENT CHANCE ONE WILL BE NEEDED FOR THE SRN INNER WATERS.

LOCALLY GUSTY NE WINDS MAY AFFECT THE INNER WATERS SUN A.M....
AND WILL BE MORE LIKELY...STRONGER AND WIDESPREAD MON A.M..

A SHALLOW MARINE INVERSION WILL BRING AREAS OF DENSE FOG WITH
VSBYS OF 1 NM OR LESS...MAINLY FOR THE NORTHERN WATERS TODAY.
PATCHY DENSE FOG WITH VSBYS 1 NM OR LESS IS LIKELY ACROSS THE
REST OF THE COASTAL WATERS THIS A.M.. DENSE FOG MAY BE MORE
WDSPRD ACROSS THE SOUTHERN AND INNER WATER TONIGHT/SAT A.M..

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...DENSE FOG ADVISORY IN EFFECT UNTIL 9 AM PST THIS MORNING FOR
      ZONES 34-35. (SEE LAXNPWLOX).
     HIGH SURF ADVISORY IN EFFECT UNTIL 9 AM PST SUNDAY FOR ZONES
      34-35. (SEE LAXCFWLOX).
     BEACH HAZARDS STATEMENT IN EFFECT FROM 9 AM PST THIS MORNING
      THROUGH SUNDAY MORNING FOR ZONE 39. (SEE LAXCFWLOX).
     HIGH SURF ADVISORY IN EFFECT FROM 9 AM THIS MORNING TO NOON
      PST SUNDAY FOR ZONES 40-41-87. (SEE LAXCFWLOX).
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS IN EFFECT UNTIL 9 PM
      PST SUNDAY FOR ZONE 645. (SEE LAXMWWLOX).
     SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PST MONDAY FOR
      ZONES 670-673-676. (SEE LAXMWWLOX).

&&

$$

PUBLIC...KAPLAN
AVIATION...DB
MARINE...DB
SYNOPSIS...KAPLAN

WEATHER.GOV/LOSANGELES



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